An estimated 100 million Americans suffer from neuropathic pain, a type of chronic pain caused by nerve damage or a malfunctioning nervous system that carries pain signals to the brain. The pain is not precipitated by a physical event such as accidentally hitting your thumb with a hammer. It can be a result of a number of things, including injury, infection, metabolic disease or a traumatic event. People often describe neuropathic pain as burning, tingling, pins and needles, and shooting or stabbing pain.

Chronic neuropathic pain is difficult for doctors to treat because it doesn’t respond well to common pain medications. Current treatments include medications, nerve blocks, implantable devices and physical therapy. Approximately $530 billion is spent annually in caring for people with neuropathic pain. It can cause marked disability in some people, with many unable to work or be productive. Patients not only have pain, but they can become depressed, have trouble thinking clearly or falling sleep. The medications prescribed often impact cognition and executive function, and there are significant risks for drug toxicity and addiction. There is an unmet need for safe and more effective pain therapies.

Tammy Durfee of Kansas City, Missouri, woke up one morning with a pain in her hip that was so severe she couldn’t get out of bed. Doctors couldn’t figure out what was causing the pain, and nothing seemed to relieve it. “I couldn’t sit still. I was always fidgeting and moving around to try and get comfortable, but I never could,” says the 56-year-old pharmacy supervisor. Over the next eight years, she would try electronic nerve stimulators, cortisone shots, narcotics and other medications. Some treatments didn’t work at all; others would work for a little while, and then stop.

An evaluation of her brain activity showed that brainwaves were misfiring, sending phantom pain signals to parts of her body. Her neurosurgeon diagnosed cerebral dysrhythmia as the cause of her neuropathic pain, and recommended a radiation procedure. But after learning her insurance wouldn’t cover it, Durfee started researching alternative treatment options. She found a center in Switzerland that treats patients like her with MRI-guided focused ultrasound, and then saw that the University of Maryland Medical Center was recruiting for a clinical trial of the same procedure. “After reading about the Switzerland study and how it was successful there, I just went for it,” says Durfee. She travelled to Baltimore and had the focused ultrasound procedure on September 13, 2018.

MRI-guided focused ultrasound is a novel approach to treating neuropathic pain that does not use radiation or invasive surgery. Instead, doctors use acoustic energy to ablate cells within the body. Magnetic resonance imaging (MRI) allows doctors to define the target inside the body and create a heat map so they know exactly where to aim. In this case, doctors guided ultrasound waves through Tammy Durfee’s skin and skull to precisely target the central lateral nucleus of the thalamus, which serves as the brain’s message relay center.

“We have pioneered a technique for high-resolution structural imaging of the thalamus and brain, which allows us to perfectly localize and target the nucleus responsible for amplifying the neuropathic pain network,” says Dr. Gandhi. He notes that every person’s skull shape and brain structure is different; for this reason, a personalized approach for every patient is necessary.

Before starting the procedure, Durfee’s head was shaved and a metal frame affixed. She laid face up in an MRI machine as the surgical team attached her head frame to the focused ultrasound transducer, which converts sound energy to heat energy. Chilled water circulated around her head to keep it cool during the three-hour procedure. Durfee was awake the entire time. Doctors gradually heated up the target, all the while getting real-time feedback from Durfee to learn whether she was experiencing more or less pain, and to make sure she wasn’t having any unwanted side effects.

“Imagine a race where all the runners have different obstacles on their way to the finish, but they all must reach the target at the exact same moment,” says Howard M. Eisenberg, MD, professor and chair of neurosurgery at UMSOM and neurosurgeon at UMMC. “That is what we are doing with focused ultrasound.”

Once doctors were sure they had identified the exact target, they increased the temperature and created bilateral lesions, effectively destroying the part of the brain responsible for sending pain signals to Durfee’s hip and leg.

When the treatment was over, Tammy Durfee got up off of the MRI table and did something she hadn’t been able to do in years. She danced. “I feel great,” Durfee says. “I’m able to do fun things with my grandkids again, like go to Legoland and the zoo.”

Currently, the study is limited to treat certain indications of neuropathic pain, which are radiculopathy (sciatica), spinal cord injury and phantom limb pain. If this study is a success, then the next step is to hold a larger trial and expand to other types of neuropathic pain that are widespread, such as diabetic neuropathy pain.

The clinical trial of focused ultrasound to treat neuropathic pain is currently recruiting qualified patients. UMMC is the only treatment site. The Focused Ultrasound Foundation is funding the study. Dr. Eisenberg is a consultant to Insightec. For more information about the trial, please contact Charlene Aldrich, RN, MSN, clinical research manager, at 410-328-5332.

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About the University of Maryland Medical Center

The University of Maryland Medical Center (UMMC) comprises two hospitals in Baltimore: an 800-bed teaching hospital – the flagship institution of the 14-hospital University of Maryland Medical System (UMMS) – and a 200-bed community teaching hospital, UMMC Midtown Campus. UMMC is a national and regional referral center for trauma, cancer care, neurological care, cardiac care, diabetes and endocrinology, women’s and children’s health, and has one of the largest solid organ transplant programs in the country. All physicians on staff at the flagship hospital are faculty physicians of the University of Maryland School of Medicine. At UMMC Midtown Campus, faculty physicians work alongside community physicians to provide patients with the highest quality care. UMMC Midtown Campus was founded in 1881 and is located one mile away from the University Campus hospital.

About the University of Maryland School of Medicine

Commemorating its 210th Anniversary, the University of Maryland School of Medicine was chartered in 1807 as the first public medical school in the United States. It continues today as one of the fastest growing, upper-tier biomedical research enterprises in the world -- with 43 academic departments, centers, institutes, and programs; and a faculty of more than 3,000 physicians, scientists, and allied health professionals, including members of the National Academy of Medicine, and distinguished recipient of the Albert E. Lasker Award in Medical Research. With an operating budget of more than $1 billion, the School of Medicine works closely in partnership with the University of Maryland Medical Center and Medical System to provide research-intensive, academic and clinically-based care for more than 1.2 million patients each year. The School has 1,307 students, 685 residents, 562 fellows, and nearly $450 million in extramural funding, with more than half of its academic departments ranked in the top 20 among all public medical schools in the nation in research funding. As one of the seven professional schools that make up the University of Maryland, Baltimore campus, the School of Medicine has nearly 7,000 total employees. The combined School and Medical System (“University of Maryland Medicine”) has a total budget of $5 billion and an economic impact of nearly $15 billion on the state and local community. The School of Medicine faculty, which ranks as the 8th-highest public medical school in research productivity, has been an innovator in translational medicine with 600 active patents and 24 start-up companies. The School works locally, nationally, and globally, with research and treatment facilities in 36 countries around the world. Visit medschool.umaryland.edu